There are some general guidelines you can find here: https://docs.aws.amazon.com/quickstart/latest/vpc/architecture.html
Every environment is different, you should consult with your AWS Solutions Architect for specific guidance.
I've always used this reference document. It's a great little "Cliff Note" of VPC Design.
There are several approaches to consider when implementing an AWS VPC in an AWS account. In addition to this, some important things to consider are flexibility between and outside of AWS accounts.
1/ When you consider your disaster recovery plan, you must ensure that there is no overlap or conflict with your local subnet CIDR.
2/ When you want to advertise a Virtual Private Cloud (Amazon VPC) route to your on-premises network through an AWS Direct Connect VIF BGP session, you can consider the longest/shortest VPC CIDR prefix to decide the route.
3/ VPC peering is also the point where you want to connect two Amazon VPCs
Hope it helps.
Transit VPC DR Cross-Region Replication Best Practicesasked 5 months ago
Direct Connect Hide VPC CIDR Blocks from BGP PeerAccepted Answerasked 3 years ago
Cloudformation - Update CIDR Range in Stack WITHOUT Terminating All RDS, ELB's InstancesAccepted AnswerMODERATORasked 4 years ago
S2S VPN host address within CIDR range of VPC (10.0.0.0/16)Accepted Answerasked 3 months ago
VPC and Subnets CIDR Best Practices?asked 2 months ago
Is the Overlay IP CIDR range for SAP on AWS just a secondary CIDR range added to same VPC?Accepted Answerasked 3 months ago
Secondary CIDR VPC block - Direct ConnectAccepted Answerasked 4 years ago
VPC/CIDR IPv4 issueasked 6 months ago
CIDR for VPC creation on below use caseasked 5 months ago
Have a VPC using a 10.1.0.0/16Accepted Answerasked 5 years ago